CHESTER COUNTY, Pa. - It's been 10 days since a 20-year-old man was seen in Chester County, and now police say they are searching for the missing endangered person.A missing endangered person advisory was issued for Jonathan Peter, 20, after he was last spotted near New Hampshire Lane in West Bradford Township on May 3 around 10:15 p.m.On Saturday, Pennsylvania State Police posted an alert that they were conducting a search of the area with the Pennsylvania Wilderness Search and Rescue.They are asking the public to use caution due to more vehicle and pedestrian traffic.Peters is described as being 6 feet 2 inches tall, weighing about 160 pounds with blue eyes and brown hair.